*限制输入数字字母的js*

            function limitInput()
            {
                var key = window.event.keyCode;
                if( (key>32 && key<48)    ||
                    (key>57 && key<65)    ||
                    (key>90 && key<97)    ||
                    (key>122 && key<127))
                    window.event.returnValue = false;
            }